build: enable -Wswitch-default

In case the surrounding code handles missing cases break, otherwise add
a g_assert_not_reached().

The generated parser code triggers this as well, so disable it there only.

gicallableinfo.c

@@ -77,6 +77,8 @@ signature_offset (GICallableInfo *info)
     case GI_INFO_TYPE_SIGNAL:
       sigoff = G_STRUCT_OFFSET (SignalBlob, signature);
       break;
+    default:
+      g_assert_not_reached ();
     }
   if (sigoff >= 0)
     return *(guint32 *)&rinfo->typelib->data[rinfo->offset + sigoff];

giconstantinfo.c

@@ -166,6 +166,8 @@ g_constant_info_get_value (GIConstantInfo *info,
 	    case GI_TYPE_TAG_DOUBLE:
 	      DO_ALIGNED_COPY(&value->v_double, &rinfo->typelib->data[blob->offset], gdouble);
 	      break;
+	    default:
+	      g_assert_not_reached ();
 	    }
 	}
     }

gifieldinfo.c

@@ -337,12 +337,16 @@ g_field_info_get_field (GIFieldInfo *field_info,
 			  g_base_info_get_name ((GIBaseInfo *)field_info),
 			  g_base_info_get_type (interface));
 		break;
+	      default:
+		break;
 	      }
 
 	    g_base_info_unref ((GIBaseInfo *)interface);
 	    break;
 	  }
 	  break;
+	default:
+	  break;
 	}
     }
 
@@ -513,12 +517,16 @@ g_field_info_set_field (GIFieldInfo     *field_info,
 			  g_base_info_get_name ((GIBaseInfo *)field_info),
 			  g_base_info_get_type (interface));
 		break;
+	      default:
+		break;
 	      }
 
 	    g_base_info_unref ((GIBaseInfo *)interface);
 	    break;
 	  }
 	  break;
+	default:
+	  break;
 	}
     } else {
       switch (g_type_info_get_tag (type_info))

girffi.c

@@ -102,6 +102,8 @@ gi_type_tag_get_ffi_type_internal (GITypeTag   tag,
         return &ffi_type_pointer;
       else
         return &ffi_type_void;
+    default:
+      break;
     }
 
   g_assert_not_reached ();

girnode.c

@@ -923,6 +923,8 @@ _g_ir_node_can_have_member (GIrNode    *node)
     case G_IR_NODE_FIELD:
     case G_IR_NODE_XREF:
       return FALSE;
+    default:
+      g_assert_not_reached ();
     };
   return FALSE;
 }
@@ -2305,6 +2307,8 @@ _g_ir_node_build_typelib (GIrNode         *node,
 	    blob->size = strlen (constant->value) + 1;
 	    memcpy (&data[blob->offset], constant->value, blob->size);
 	    break;
+	  default:
+	    g_assert_not_reached ();
 	  }
 	*offset2 += ALIGN_VALUE (blob->size, 4);
 

girparser.c

@@ -3092,6 +3092,8 @@ start_element_handler (GMarkupParseContext *context,
 		      ctx, error))
 	goto out;
       break;
+    default:
+      break;
     }
 
   if (*error == NULL && ctx->state != STATE_PASSTHROUGH)

girwriter.c

@@ -505,6 +505,8 @@ write_callable_info (const gchar    *namespace,
 	case GI_DIRECTION_INOUT:
 	  xml_printf (file, " direction=\"inout\"");
 	  break;
+	default:
+	  g_assert_not_reached ();
 	}
 
       if (g_arg_info_may_be_null (arg))
@@ -529,6 +531,8 @@ write_callable_info (const gchar    *namespace,
         case GI_SCOPE_TYPE_NOTIFIED:
           xml_printf (file, " scope=\"notified\"");
           break;
+        default:
+          g_assert_not_reached ();
         }
 
       if (g_arg_info_get_closure (arg) >= 0)